Influence of active cooling on microstructure and mechanical properties of wire arc additively manufactured 5356 aluminium alloy

Abstract In order to reduce heat accumulation and subsequently its adverse effects on properties of the components in wire + arc additive manufacturing (WAAM), this study investigates the impact of a thermal management and heat mitigation of a water based active colling technique for the deposition of ER5356 alloy. The application of this simple and cost effective yet effective strategy directs towards the novel approach to improving deposition quality and thermal stability in aluminium additive manufacturing. With this method, the preform is partially submerged in a water-filled work tank in such a way that the welding surface remains above the water surface at a fixed distance, and more water is added to maintain this gap. As a heat sink, the water absorbs the heat produced during the deposition process by which heat accumulation can be averted. Single-pass multi-layer linear walls of ER5356 were deposited using the standard Gas Metal Arc Welding (GMAW) process with different thermal control techniques. By measuring the process parameters and recording the thermal history of the preforms, effects of water cooling on material properties is evaluated. The micro structure & SEM fractography is performed to evaluate the effect on impact strength and tensile strength. The results shows that this technique successfully lowers heat accumulation by 80% to 88% reduction in temperature. Surface waviness is reduced by 40% and material deposition has been increased. Wall thickness is improved and remained nearly constant. Further, the anisotropy of the mechanical properties decreased, indicating an improvement in the quality of the preform. This approach solves the challenges that come with this rapidly growing additive manufacturing process by providing a cheap and effective way to manage heat in WAAM.